Minimum-Phase Control In Sampled Systems And Study Of Non-Nyquist Sampling

In the data processing, sampling manner and recovery mode is closely relative with the data processing precision and the processing speed. The sampling theory with the cores of sampling theorem and interpolation mode has been causing many scholar's interests.In the controlling kingdom, when a minimum-phase(MP) system is sampled, the discretized transfer function may be non minimum-phase(NMP), which is not practical in many control algorithm.Based on the previous theory, we will discuss the zeros of sampled systems. We also give a sufficient condition for a class of continuous transfer function, which is in analytic form. Further, we will discuss the objects with time lag and propose a necessary and sufficient condition to be assure MP, which depends on the sampling period T and time lag coefficient T .In the practical industry, when we choose an appropriate sampling period according to some rule, based on a new type of transformation of the controllable input, we get a design for stable discrete systems in the case of chosen sampling period. The design is ended by solving a series of constants.Compared with ordinary Nyquist sampling, non-Nyquist sampling has many good superiorities. The position of spectral after non-Nyquist sampling multiple frequency periodic signals is proposed clearly based on sampling spectral coordinate. We also give one electric net voltage as an example.Aimed at the large data redundancy in modern telemetric systems, we approximate the sample data of telemetric signal and present a method. It can adjust the sampling interval adaptively without knowing the signals bandwidth and mid-frequency, which we call adaptive sampling.